Equipment for treating wells



Oct. 13, 1953 R. CRAIN 2,655,218

7 EQUIPMENT FOR TREATING WELLS Filed June 3, 1949 4 Sheets-Sheet lATfoRuEYi Filed June 3, 1949 Oct. 13,1953 R. L. CRAIN 2,655,218EQUIPMENT FOR TREATING WELLS '4 Sheets-Sheet 2 ATTOR N EY$ Filed June5', 1949 Oct. 13, 1953 R. L. CRAIN 2,655,213

EQUIPMENT FOR TREATING WELLS 4 Sheets-Sheet 3 Ewe/2:5. 6M1,

ATTOR N EYJ Oct. 13, 1953 R. L. CRAlN EQUIPMENT F OR TREATING WELLS 4Sheets-Sheet 4 Filed June 5, 1949 mmmw wvv'vvvvww vvvvwww l/Ill!kafi522:. a!adv1//IIIIIIIIIIIIIQIII% a! 4 INVENTOR.

Z6 Z- 5742' BY @YM) Patented Oct. 13, 1953 EQUIPMENT FOR TREATING WELLSRobert L. Grain, Houston, Tex., assignor to Gray Tool Company, Houston,Tex., a corporation of Texas Application June 3, 1949, Serial No. 96,941

8 Claims.

The present invention relates to equipment for permitting theintroduction of anti-corrosion inhibitors into the stream of oil beingdischarged from the well without interfering with, limiting, orcomplicating the operations normally performed on a well, and whileproviding for the essential control of the well by the use of thevarious temporary and permanent seals now used on the well during theperformance of the various operations in drilling and completing theWell.

In the flowing of oil wells, it is well-known that deposits of paraflinand the like in the well tubing reduce the efiiciency of flow therefrom.Various method and apparatus for cleaning the well have been devised,and methods are known whereby solvents, acids and other chemicals areintroduced into the well tubing to eliminate the undesirable deposits.

Up to the present time, the equipment employed for such practices hasnot been satisfactory because it has introduced complications in thestructure, particularly at the well head, which complications have madedifllcult the performance of the normal operations in drilling andcompleting the well. The equipment heretofore used has also introducedcomplications making it more diificult to provide that necessarymechanical control of the well which is essential to insure preservationof life and property.

Details of the objects and advantages of the invention referred toabove, and the nature of other objects and advantages of the inventionwill be apparent as the specification progresses.

Figures 1 through 9 are side elevational views of the equipment at andadjacent the top of the well, partly in section, showing the variousstages of the operations involved in introducing the equipment of thepresent invention into the well, for the purposes stated, whilepermitting the usual operations incident to the completion of the welland providing the mechanical control which is recognized as beingnecessary in present day practices.

Figure 10 is an enlarged sectional view of the equipment at the wellhead and adjacent thereto showing the arrangement of the parts when theequipment of the present invention has been installed, and with the wellin condition for flowmg,

Figures 11 and 12 are detail views showing respectively the lowercollector coupling of the invention and the stuffing box coupling foradjacent sections of the relatively small pipe used to deliver thetreating fluid into the well,

Figure 13 is a horizontal sectional view through a special type ofblow-out preventer which may be usefully employed in connection with thepresent invention.

It will be understood that while the equipment disclosed herein isemployed for purposes of introducing an inhibitor fluid into the well,the equipment may be usefully employed for other purposes where the samedouble conduit arrangement may be utilized.

Referring to Figures 1 through 9, the well head equipment disclosed isof the general type described in considerable detail in the patent toSmith et al., No. 2,148,327 of February 21, 1939, comprising the casingl0, lower casing head l2, the hanger l4 for the inner casing l6, and theupper casing or tubing head [8.

The present invention is adapted to cooperate with this well-knownequipment just referred to in such manner that flow tubing equipped withapparatus of the present invention may be introduced into the well, andsuspended and locked in the tubing head l8, after which the controlequipment used during the completion operationsmay be removed. Thecontrol equipment is shown as including a master drilling valve 20 ofconventional type, a blow-out preventer 22 of conventional type and ablow-out preventer 24 of special construction, as hereinafter described.

It will also be understood that the practice of completing the well atthe stage where the Christmas tree is landed on the tubing head isgenerally similar to that disclosed in the patent to Yancey No.2,241,288 of May 6, 1941.

In Figure 1, tubing 30 is shown being lowered into the well through thecontrol equipment. At this stage, all strings of casing will have beenpreviously set, and the control equipment shown is that of size adaptedfor the tubing inserting and allied operations. If a non-retrievablepacker is used, it will already have been set at this stage, and thebottom joint of the tubing 38 would be adapted to pass into the packerand open the back pressure valve'therein. As an alternative, an ordinaryretrievable hook wall packer may be passed into the well on the bottomsection of tubing 30, but these packer-devices and their operation formno part of the invention.

In the upper part of Figure 1, equipment of the present invention isshown ready tobe introduced into the control equipment during the firststep of completion of the well, there being a lower collector coupling32 connected'into the tubing between its bottom section 30 and its nextadjacent section above numbered 34. The lower collector couplingprovides for the introduction of the treating fluid into the lower endof the flow tubing, the treating fluid being supplied by a separate andsmaller pipe line, the lower section of which is shown at 36.

It will be apparent from the preliminary description just made that theapparatus provides for introducing the treating fluid into the flowtubing adjacent the lower end of the latter so that the treating fluidpasses upwardly with the flow of oil, acting all the while to preventthe accumulation of paraifin and the like in the flow tubing. Obviously,the introduction of the separate pipe section 36 into the well assemblyraises complications which must be overcome by the equipment in order topermit the necessary well completion operations with control.

The lower collector coupling is shown in detail in Figure 11. It hasupper and lower threaded sockets to rigidly connect with the ends of thetubing sections 30 and 34, and it has a fluid way therethroughcomprising the vertical portion 40 and the lateral port 42, the latter,entering the interior of the coupling, thereby providing for thedelivery of the treating fluid into the tubing adjacent the lower endthereof. The passages 48 and 42 are separated by a valve seat as shown,and this seat is normallyengaged by a ball valve member 44 which isarranged to be caused to engage its seat by pressure from the interiorof the tubing, whereby this valve member normally prevents escape of oilfrom the well upwardly through the small pipe section 36 whilepermitting downward flow of fluid under pump pressure through thesmaller pipe section 36 in order that the inhibitor chemical can beintroduced into the flowing stream of oil passing upwardly through thetubing.

In Figure 2, the lower collector coupling 32 is shown as having arrivedat a point below the upper end of the casing it, it being understoodthat alternate sections of the flow tubing and of the smaller treatingpipe will be attached or coupled to one another in a conventional mannerand lowered into the well. The smaller pipe for the inhibitor fluid isattached to the tubing at spaced points by suitable straps or brackets48. During the making up of the tubing, as just referred to, and theinsertion of same into the well, the blowout preventor 22 may be closedat any time around the larger tubing by simply lowering the tubing to anextent where the upper end of the last section of the smaller pipeattached would be below the shoes of the blow-out preventor 22, at whichtime the latter could be closed around the larger section of tubing.

As an alternative to the above, a special blowout preventor 24 may beused having shoes of special design, as shown in Figure 13. The oppositeshoes of this blow-out preventor are shown at 49 and 50, and each shoehas a large opening 52 and a relatively smaller opening 54, wherebythese shoes may grip around and seal against the exterior of the largetubing and the smaller pipe carried by the larger tubing, forming a sealas is well-known in connection with the construction and operation ofsuch blow-out preventors.

The shoes of this blow-out preventor may be moved from and toward oneanother in any wellknown manner, either by fluid power or by mechanicalpower, as is well-known in the art, a conventional arrangement for theapplication of mechanical power being indicated in Figure 13.

In Figure 3, the apparatus is shown in tha condition wherein the lowerend of the tubing has almost reached its final position adjacent thebottom of the well, and at this time, a special temporary hanger W ofthe wrap-around type may be applied to the large and small parallelpipes. This type of hanger is of a construction well-known in the art,comprising two half sections which are applied against one anotheraround the pipe and lowered into the seat of the casing or tubing headHi, this wrap-around hanger or blow-out preventor being of such size asto be capable of being lowered through the control equipment to the seatin the tubing head 18, where the hanger or preventor is locked in placeby the conventional locking screws G0 as shown in Figure 4. The generalarrangement of the half sections of this wrap-around device isillustrated in Figure 7. The two sections are provided with exteriorpacking iii to seal in the bowl of the tubing head and also withinterior packing 62 to seal around the pipes on which the device iscarried. The inner meeting faces of the two sections are provided withrespective large and small aligned semi-cylindrical grooves 62, 63 whichreceive and seal around the large and small pipes respectively. Thedevice has a circular groove 64 on its exterior wall as shown in Figure3 to receive the inner ends of the locking screws 60 when thewrap-around device is landed in the bowl of the tubing head.

Referring again to Figure 3, the upper end of the tubing is providedwith a collar 66 and a short nipple Bil to which is attached a backpressure valve assembly Til, the latter being in turn connected with aconventional landing joint of tubing 12. The back pressure valveassembly lii is only generally indicated, but it will be understood thatthis assembly is a special collar in the tubin with interior threads toremovably receive a back pressure valve arrangement as shown in Figure 5of the said Smith Patent No. 2,148,327. In that patent, a special collaris shown at 62 connecting the tubing and the hanger 74, and it will beunderstood that in the present invention, the as sembly Ill constitutessuch a special collar threaded interiorly to connect with the landingjoint 12 and the short nipple 6B, and is further provided with interiorthreads to remcvably carry the back pressure valve in the manner shownin Figure 5 of the said Smith et al. patent.

At this point, the string of pipe 36 may be reduced in diameter, forinstance, from one inch size to one-half inch size by means of a specialsteel bushing which adapts the smaller section 36 to the larger sectionof this pipe.

When the wrap-around device and the back pressure valve are loweredthrough the control equipment and landed, as shown in Figure 4, the liftnipple i2 is removed, and the well being sealed both in and around thetubing, the control equipment may then be removed leaving the well incondition illustrated in the lower part of Figure 5, the locking screws68 in the head 18 serving to hold the wrap-around device in its seat,the upper end of said device being engaged by the tubing collar 66whereby the tubing is properly suspended and sealed in the head i8.

A special well head or Christmas tree assembly indicated generally bythe letter C in Figure 5 is then made up as a unit and connected to theupper end of a short sub of pipe 82 which may, for example, beapproximately six feet in length. In a manner to be hereinafterdescribed, and upon removal of the wrap-around device W. this assembly 0is lowered into and onto the well head equipment in a manner generallysimilar to the procedure described in the said Yancey Patent 2,241,288in order to complete the well with all of the advantages described insaid patent, but the assembly is of modified and improved constructionas illustrated in Figure 10, in order to provide for the particularpractices of the invention.

The assembly is best illustrated in Figure 10 which shows the conditionof the equipment after completion of the well.

An upper collector coupling is shown at 84, same being connected intothe tubing at the upper end of the sub 82. The coupling 84 has asomewhat restricted bore 86' threaded at its upper end as at 88 toreceive the short interior tubing section 90, and it is threaded at itslower end as at 92 to receive the threaded upper end of the tubingsection 82. The coupling is chambered above its restriction as at 94,and this enlarged portion is interiorly threaded to connect with therelatively large outer section of tubing 85 which constitutes a slickjoint capable of adjustment through the permanent tubing hanger in amanner hereinafter described. The coupling 84 has a vertical fluid wayIflil therethrough in order to establish communication for the inhibitorfluid on the inside of the slick joint 96 to the small pipe 36'.

The upper end of the slick joint passes through the stufling box of thepermanent hanger S, which is of construction the same as described inthe said Yancey patent with respect to the hanger S of that patent, i.e., a stuffing box hanger adapted to be mounted on tubing and landedthrough control equipment into the tubing head, but permittingadjustment of the tubing therethrough to permit operations in the wellas described in said Yancey patent. The upper end of the slick joint 96is threaded as at I82 into the lower end of a flanged well head fittingI84 provided with a suitable inlet I86 and valve I28 for controlling theinlet of the inhibitor fluid. The fitting I04 is further provided with astuffing box I89 to receive the upper end of the inner joint of tubing98, and there is a flanged adaptor IIEl mounted above the fitting I94 onwhich the valve I I2 of the Christmas tree is carried, said valvecorresponding with Christmas tree valve 64 of Figure 5 of the saidYancey Patent 2,241,288.

With the construction as shown in Figure and with the equipment landedand secured in the manner hereinafter described, it will be understoodthat the inhibitor liquid or chemical may be introduced into the wellthrough the valve I08 and downwardly through the hollow space H4 in thefitting I04, thence downwardly through the space between the inside ofthe slick joint 96 and the outside of the tubing section 92, through thepassage I GO in the upper collector coupling 84 and thence downwardlythrough the smaller pipe sections 36' and 36 for the treating fluid, thetreating fluid discharging inwardly into the lower end of the tubing 34via the passages 40 and 42 in the lower collector coupling; as shown inFigure 11. With this construction, the reagent being used to preventaccumulation of paraflin and the like in the tubing will join with theupward flow of oil through the tubing and will be carried upwardly bythe natural flow of oil from the well.

Referring now to Figure 5, and with the assembly C made up and suspendedfrom the Kelly joint K as shown, back pressure valve I0 may be tested todetermine if the tubing has accumu-- lated pressure from the bottom ofthe well. it has, the sub 82 is connected into the upper end of the backpressure valve 10, and the pumps are operated and mud is circulateduntil such time as the pressure within the tubing is safely balanced.The short section of pipe 83 and the back pressure valve assembly IIImay then be removed, and the assembly C lowered to connect the pipesection 82 into the collar 66, as shown in Figure 6, and the parts arethen made up permanently with the lower end of the passage I60 in theupper collector coupling 84 (Figure 10) positioned in alignment with thetreating pipe section 36, a coupling II6 being used in the small pipesections 35' to finally make up that smaller pipe and permit itsconnection into the lower end of the passage I88 in the lower collectorcoupling 84. Suitable clamps H8 are utilizedto secure the smaller pipesections 38 onto that portion of the flow tubing designated as 82.Clamps II8 are placed above and below the coupling I I6 to prevent thesmaller string of pipe from parting under pressure.

After determining by test that there is no dangerous pressure within thecasing I6, the locking screws 60 in the tubing head may be retracted andthe wrap-around blow-out preventor W may then be removed, as shown inFigure '7, and thereafter the entire assembly is lowered into the well,as illustrated in Figure 8. During this lowering operation, the uppercollector coupling passes into the well, and the stufling box hanger Sis landed and locked in the tubing head I 8, and the tubing may beadjusted through this hanger in the manner described in the said YanceyPatent 2,241,288 in connection with any washing operations, whilepermitting the lower flanged end of the fitting I 04 to ultimately reston and be bolted to the upper flange of the tubing head I8 as shown inFigure 9. Thereafter, the Kelly joint may be removed from above theChristmas tree master manifold control valve I I2, and any desiredcontrol valves or fittings forming a further part of the Christmas treemay then be connected above the said valve I I2 as shown in Figure 9where an arrangement of valves and choke manifolds is shown.

The details of the stuffing box coupling H6 are shown in Figure 12,comprising an enlarged tubular member I20 connected by a collar to thelower section of pipe and being adapted to slidably receive the lowerend of the upper section of :pipe therein with a suitable stuifing boxar-" rangement being provided at the upper end of the member I20including packing which may be tightened by adjustment of the threadedcap I22 carried on the upper end of the member I28.

It will be understood that when the equipment is in the condition shownin Figure 8, with the hanger S seated and locked in the tubing head I8,and with the master manifold control valve I I2 and the Kelly Kconnected as shown, any washing and packer setting operations may becarried out, and the tubing strings may be raised, lowered or rotated,as desired.

With the above construction, it will be understood that the well may becompletedin the general manner described in the said Smith Patent2,148,327 and the said Yancey Patent 2,241,288, with the specialequipment described and particularly illustrated in Figure 10 installedduring the normal completion operations and with the well under controlas described, the various necessary steps in completing the well asdescribed in the saidpatents being capable of being performed eventhough this special equipment as described is introduced. With the wellcompleted, the inhibitor chemical may be introduced downwardly throughthe smaller pipe sections 36 and 35', this chemical entering the tubingthrough the lower collector coupling and passing upwardly through thetubing with the normal flow of oil to accomplish the purposes for whichthe special equipment is intended. It will further be apparent that thecompleted well is in such condition that the control equipment may againbe re-installed, after completion, to accomplish any of the operationssubsequent to completion as are referred to in the said patents.

It will be understood that certain of the equipment only generallydisclosed herein is now wellknown in the art. For instance, the casinghanger l4 illustrated in Figure 10 is generally of the type disclosed inthe patent to Roye, 2,207,469, July 9, 1940, in that it is a doubletapered hanger provided with slip suspension means, it also beinggenerally indicated that this hanger may be provided with interiorpacking to seal around the casing. Oi course, various types of casinghangers might be employed in the well head wherein the practices of thisinvention are carried out.

While the fittings mounted on the well head such as 104 are of specialdesign, it will be obvious that they may be considered as special partsof the Christmas tree in that they are assembled with the Christmas treemanifold valve HZ as shown in Figure 5 and thereafter ultimately landedon the casing or tubing head i 5 after the control equipment is removed.

It will be apparent that the circulating system for the treating fluidcomprises an upper conduit portion constituted by the space between theouter wall of the tubing 90 and the inner wall of the larger tubing 96(Figure and a lower portion constituted by the relatively small pipes 35and 36' carried in parallel relationship along the length of the tubingproper.

The terminology used in the specification is for the purpose ofdescription and not limitation, the scope of the invention being definedby the claims.

I claim:

1. Oil well apparatus of the character described for use in an oil wellhaving a casing and oil well flow tubing therein, comprising: an uppercoupling in the casing having a first fluid way therethroughcommunicating with the upper end of the flow tubing and also having asecond separate fluid way therethrough non-communicating with the flowtubing, a pipe section smaller than the flow tubing and having means forattachment to said coupling for communication with said second separatefluid way to convey treating fluid therefrom to the bottom of the flowtubing, well head equipment comprising a fitting having an outlet fordischarging oil from the flow tubing and an inlet for receiving thetreating fluid, and a pair of tubes arranged one within the other andconnected between said coupling and said fitting, providing conduitsseparate from one another, one of said conduits extending between saidinlet and said second separate fluid way and the other of said conduitsextending between said outlet and the first fluid way communicating withthe flow tubing.

2-. Oil wall apparatus of the character described for use in an oil wellhaving a casing and oil well flow tubing therein, comprising; a casinghead, a hanger seat in said head, an

upper coupling having a first fluid way there--- through communicatingwith the upper end of the flow tubing and also having a second separatefluid way therethrough non-communicating with the flow tubing, a pipesmaller than the flow tubing connected to said coupling andcommunicating with said second separate fluid way therein to circulatetreating fluid in the well, a pair of tubes arranged one within theother and connected to said coupling to extend upwardly therefromproviding an inner conduit leading from the interior of the flow tubingand an outer conduit between said tubes communicating with said secondseparate fluid way, a hanger mounted on the exterior of the said outertube and adapted to he landed in said seat to seal oiT the upper end ofthe well casing, and a Christmas tree mounted on said casing headcomprising a fitting having separate means to seal off around the upperends of said tubes, said fitting having an inlet communicating with saidouter conduit and an outlet communicating with said inner conduit.

3. Oil well apparatus of the character described ior use in an oil wellhavin a casing, a casing head, and oil well flow tubing therein,comprising; a Christmas tree having a hollow fitting for mounting on thecasing head and provided with an inlet to and an outlet from its hollowinterior, a pair of tubes arranged one within the other providing aninner conduit within said inner tube and an outer conduit between saidtubes, said fitting having means to seal off around the upper ends ofsaid tubes and to secure the same in dependent relationship therefromwith said inlet communicating with said outer conduit and said outletcommunicating with said inner conduit, and a coupling carried at thelower ends of said tubes and adapted to be secured to the upper end ofthe flow tubing, said coupling having a first fluid way therethroughcommunicating said inner conduit with the flow tubing and a second fluidway therethrough non-communicating with said flow tubing, a pipe sectionsmaller than the well tubing tachment of control valves and the like tosaid side and top openings, a pair of tubes arranged one within theother providing an inner conduit and an outer conduit between saidtubes, said fitting having means adjacent its bottom opening to seal offwith the upper end of said outer tube to establish communication forflow of fluid between said outer conduit and said side opening, saidinner tube extending upwardly through the interior of said fitting andhaving means to seal ofi its upper end in said top opening to establishseparate communication for flow of fluid from said inner conduit throughsaid top opening, and a coupling carried at the lower ends of said tubesand adapted to be connected to the upper end of the flow tubing, saidcoupling having a first fluid way therein communicating said innerconduit with the well tubing and a second fluid way therein, and a pipesection connected to said coupling in dependent relationship therefromand in communication with said outer conduit through said second fluidway for circulation of treating fluid through the well.

5. Oil well apparatus for circulating a treating fluid in a well havinga well head, a casing, and oil well flow tubing therein, comprising; aseparate conduit to circulate the treating fluid into the flow tubing insaid well through the lower end thereof, a lower portion of said conduitformed of sections of pipe smaller than the flow tubing with means toconnect these sections to one another and to the outside of the flowtubing extending in parallel relationship therewith, and an upperportion of said conduit formed of a tubing larger than the flow tubingwhich is adapted to be positioned in surrounding relationship withrespect to the upper end of the flow tubing, a hollow coupling adaptedto be connected in the flow tubing and having a second separate fluidway extending therethrough in non-communication with said flow tubing,said coupling having means for attachment thereto of the uppermost ofsaid smaller pipe sections and the lower end of said larger tube andboth being in communication with each other through said second fluidway, and a Christmas tree on the well head having separate flow openingstherein, means on said Christmas tree to seal off between the upper endsof said flow tubing and said larger tube and the surrounding Christmastree wall, one of said separate flow openings being in communicationwith said flow tubing and the other of said flow openings being incommunication with" the conduit between said flow tubing and said largertube.

6. Oil well apparatus of the character described for use in an oil wellhaving a casing and oil well flow tubing therein, comprising; a casinghead having a hanger seat therein, a Christmas tree mounted on saidcasing head, a pair of tubes arranged one within the other providing aninner conduit and an outer conduit between said tubes, said tubes beingattached to and depending from said Christmas tree through said casinghead, said Christmas tree having a pair of flow openings therein, meansto seal off the upper end of the outer of said tubes in communicatingrelationship with one of said openings and to seal oil the upper end ofthe inner of said tubes in communicating relationship with the other ofsaid openings, a coupling having a first fluid way extendingtherethrough communicating the inner conduit with the flow tubing andhaving a second separate fluid way therethrough connecting the outerconduit with a separate piping system extending down into the well, saidouter of said tubes having a polished exterior with a hanger mountedthereon adapted to he landed in said hanger seat, said hanger having astuffing box therein surrounding the polished portion of said outer ofsaid tubes whereby the flow tubing may be vertically adjusted in theperformance of operations incident to the completion of the well.

7. Oil well apparatus of the character described for an oil well havinga casing and an oil well fiow tubing therein, comprising; a casing headhaving a hanger seat therein, a, Christmas tree mounted on said head andhaving a. pair of flow openings with flow lines extending therefrom, apair of tubes depending from said Christmas tree and arranged one withinthe other forming inner and outer flow conduits, said Christmas treehaving means to seal off around the upper end of each of said tubes toestablish separate channels of flow between one of said openings and oneof said conduits and the other of said openings and the other of saidconduits. and a hollow coupling carried at the lower ends of said tubeshaving means for attachment to the flow tubing to establishcommunication for flow between the upper end of said flow tubing andsaid inner flow conduit, said coupling having a second separate fluidway therethrough in non-communication with said flow tubing and incommunication with said outer flow conduit, means connected to saidcoupling and in communication with said second separate fluid waytherein for establishing communication 01 flow between said secondseparate fluid way and the lower end of the flow tubing.

8. 011 well apparatus of the character described for use in an oil wellhaving a casing and oil well flow tubing therein, comprising; a lowercoupling attached to the flow tubing adjacent the lower end thereof andhaving a fluid way extending therethrough in communication with the flowtubing, said coupling having a second fluid way therein with a separateinlet which communicates with said flrst fluid way for injection oftreating fluid into the flow tubing, an upper coupling for attachment inthe flow tubing adjacent the upper end thereof and having a first fluidway therethrough communicating with the flow tubing, said upper couplinghaving a second fluid way therethrough non-communicating with said firstfluid way for downward passage of the treating fluid, a pipe sectionsmaller than the flow tubing having means for attaching the same to theouter wall of the flow tubing and for connecting the same to said upperand lower couplings to establish communication between the respectivesecond fluid ways of each, and well head equipment comprising a wellhead having a hanger seat therein, a hanger supported in said hangerseat above said upper coupling to seal off the upper end of the wellcasing, said well head equipment having means providing a conduitconnected to the upper coupling for upward passage of oil from the flowtubing and a separate conduit extending from above said hanger to thesecond fluid way in said upper coupling to convey the treating fluiddownwardly into said pipe section.

ROBERT L. CRADT.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 404,397 Geiser June 4, 1889 1,500,400 Larsen July 8, 19241,944,573 Raymond et al. Jan. 23, 1934 2,148,327 Smith et al. Feb. 21,1939 2,177,164 Baash Oct. 24, 1939 2,207,469 Roye July 9, 1940 2,241,288Yancey May 6, 1941 2,241,333 Smith May 6, 1941 2,244,684 Foran June 10,1941 2,247,023 Humason et al June 24, 1941 2,293,442 Montgomery Aug. 18,1942 2,335,355 Penick et a1 Nov. 30, 1943 2,445,249 Sproull July 13,1948

